Definition

Group B streptococcal (GBS) disease is a bacterial infection.

GBS can cause illness in newborn babies, pregnant women, the elderly, and adults with other chronic medical conditions, such as
diabetes
or liver disease. In newborns, it is the most common cause of a blood infection called
sepsis
and
of meningitis, which is an infection of the fluid and lining surrounding the brain.

This following information covers GBS in pregnant women and their babies.

Causes

GBS is caused by the bacteria
Streptococcus agalactiae
. These bacteria live in the gastrointestinal and genital tracts. They are found in the vaginal or rectal areas of 10% to 35% of all healthy adult women.
Only a small number of babies who are exposed to the bacteria will become infected. If infection occurs, it can be serious.

Newborn babies can become infected with GBS in three ways:

Before birth, bacteria in the vagina can spread up the birth canal into the uterus and infect the amniotic fluid surrounding the fetus. The baby becomes infected by inhaling the infected fluid.

Symptoms

In pregnant women, GBS infections can sometimes cause inflammation or irritation of the lining of the uterus called endometritis, infection of the uterus and amniotic sac called amnionitis, and loss of pregnancy due to infection.

Symptoms of endometritis and amnionitis may include:

Fever

Abdominal pain

Bad odor of amniotic fluid

Doctors are especially concerned about how GBS infections affect young infants. The disease can occur early in newborns (early-onset) or late (late-onset). Early-onset GBS disease usually causes illness within the first 24 hours of life. However, illness can occur up to 3 days after birth. Late-onset disease usually occurs at 3 to 4 weeks of age. It can occur any time from 4 days to 3 months of age.

Symptoms of GBS include:

Unstable temperature—low or high

Breathing problems

Not eating well

Irritability

Difficulty waking

Weakness or lacking energy—in late-onset disease

Diagnosis

GBS can be diagnosed in a pregnant woman at an obstetric office visit. Testing for GBS should be done about one month before the baby is due. The doctor swabs the vagina and rectum and sends this sample to a laboratory to test for GBS. Test results are available in 24-48 hours. Treatment usually does not begin until labor starts.

Your baby's bodily fluids may be tested. This can be done with:

Blood tests

Culture tests

Urine tests

Spinal fluid test

Treatment

For Mom

If you test positive for GBS or are at high risk, your doctor may recommend giving you antibiotics through an IV during labor and delivery. Antibiotics will reduce the risk that your baby will get sick after birth. Even with screening and antibiotic treatment, some babies can still get GBS disease.

It is generally not recommended that women take antibiotics before labor to prevent GBS unless GBS is identified in the urine. It is not as effective at preventing illness unless it is given after labor has begun.

For Baby

If the doctor suspects strep B infection, a newborn might be kept in the hospital a couple of extra days for monitoring, which will include blood and urine tests. A baby diagnosed with GBS will be treated with IV antibiotics for 10 days. If GBS is suspected, antibiotics may be started before a diagnosis is made. Seek medical care right away if your baby has any of the symptoms of GBS infection.

Prevention

Methods to prevent GBS
may
include:

Screening pregnant women at 35-37 weeks—If GBS is found through the screening, IV antibiotics are given during labor and delivery.

For women who did not receive screening at 35-37 weeks,
an alternate strategy gives antibiotics during labor and delivery to women who:

Are carriers of GBS bacteria

Have previously had an infant with GBS disease

Have GBS bacterium
at any time during
the present pregnancy

Go into labor or have rupture of the membranes before the fetus has reached an estimated gestational age of 37 weeks

Have rupture of membranes for 18 hours or more before delivery

Have a fever during labor

Have a urinary tract infection with GBS

Revision Information

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Provisional Recommendations for the Prevention of Perinatal Group B Streptococcal Disease. Centers for Disease Control and Prevention website. Available at:
http://www.cdc.gov/groupbstrep/guidelines/downloads/provisional-recommendations-508.pdf. Updated July 2010. Accessed August 14, 2013.